AERI PROF: AERI Profiles of Water Vapor and Temperature
High temporal resolutions of temperature and water vapor profiles through the planetary boundary layer are being retrieved from the high resolution spectral data observed by the Atmospheric Emitted Radiance Interferometer (AERI).
Information Last Updated: August 2005
General Description
These profiles are nominally retrieved every 8 minutes (the AERI's sampling rate) and greatly supplement other methods of determining the structure of the lower atmosphere (radiosondes, raman lidar, RASS). The vertical resolution is 100 meters at the surface and gradually increases to 250 meters at 3 kilometers.
As with all retrieval algorithms, the profiles are the result of taking the inverse of the radiative transfer equation. Even though over 400 individual points from the AERI spectrum are used, the problem is still ill-defined, thus constraints are needed to prevent the inversion from becoming unstable. The surface observations of temperature, pressure, and moisture are critical, as the retrieved profiles become increasingly more dependent on them with altitude. The surface observations are from the Surface Meteorological Observation System (SMOS). The cloud-base height from the micropulse lidar and the total precipitable water vapor in the column from the microwave radiometer also are used to constrain the retrieval.
Statistical first-guess profiles are also used to prevent the inversion from becoming unstable. These profiles were derived from a historical database of radiosondes and model calculations (at AERI resolution) from those radiosondes at the ARM Southern Great Plains (SGP) site. These profiles are smoothed to remove all but the gross structure, allowing the retrieval process to put the structure back in.
Note that the iterative retrieval process uses a "bias" spectrum to account for errors in the forward model and in any instruments. This spectrum is calculated by selecting clear-sky cases where radiosonde and AERI data are available. This spectrum is then added to each iteration's forward calculation during the retrieval.
The Algorithm and Methodology
Flow Chart
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Input Data Sources
sgpaeri01ch1C1.a1 - AERI observed radiance data (5 - 18 microns)
sgpaeri01ch2C1.a1 - AERI observed radiance data (3.3 - 5 microns)
sgp30smosE13.a1 - surface pressure, temperature, and vapor pressure
sgpmwrlosC1.a1 - microwave radiometer water vapor, liquid water, and IR thermometer data
sgpmplC1.a0 - micropulse lidar cloud base heights
sgpblcC1.a1 - Belfort laser ceilometer cloud base heights
Output Products
Here are some examples:
Example #1 - example profiles of temperature and water vapor against a nearby radiosonde
Data Quality Assessment Included
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Known Algorithm Caveats
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VAP History
Current Version
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Reprocessing History
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Compatibility of Results from Different Version
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Plans for Future Modifications
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Other
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Output Products
Descriptions of Products
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Examples of Output Data and Output Filename Structure
sgpaeriprofC1.c1 - retrievals of temperature and water vapor from the AERI
Description of Data Quality Fields
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Status and Location of Results
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Notes for Data Users
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Related Products Data and Links
Ordering Data
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Links to Notification File
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Link to Data Release History
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Other
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Frequently Asked Questions
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Contacts
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VAP Specific Glossary and Acronyms
For ARM-wide acronyms, see the ARM Acronyms/Glossary.
Citable References
Smith, W.L., R.O. Knuteson, H.E. Revercomb, F.A. Best, R.G. Dedecker, and H.B. Howell. 1993. "GB-HIS: A measurement system for continuous profiling of boundary layer thermodynamic structure." 8th Symposium on Meteorological Observations and Instrumentation, AMS 73rd Annual Meeting.
Feltz, W.F. 1994. Meteorological applications of the Atmospheric Emitted Radiance Interferometer (AERI). Master's Thesis, University of Wisconsin - Madison.
